Three-dimensional batteries and methods of manufacturing the same

ABSTRACT

Various methods and apparatus relating to three-dimensional battery structures and methods of manufacturing them are disclosed and claimed. In certain embodiments, a three-dimensional battery comprises a battery enclosure, and a first structural layer within the battery enclosure, where the first structural layer has a first surface, and a first plurality of conductive protrusions extend from the first surface. A first plurality of electrodes is located within the battery enclosure, where the first plurality of electrodes includes a plurality of cathodes and a plurality of anodes, and wherein the first plurality of electrodes includes a second plurality of electrodes selected from the first plurality of electrodes, each of the second plurality of electrodes being in contact with the outer surface of one of said first plurality of conductive protrusions. Some embodiments relate to processes of manufacturing energy storage devices with or without the use of a backbone structure or layer.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 U.S.C. section 119(e) to: (i)U.S. Provisional Application No. 60/884,836, entitled “Electrodes ForThree Dimensional Lithium Batteries And Methods Of ManufacturingThereof,” filed on Jan. 12, 2007; (ii) U.S. Provisional Application No.60/884,828, entitled “Three-Dimensional Batteries and Methods ofManufacturing Using Backbone Structure,” filed on Jan. 12, 2007; and(iii) U.S. Provisional Application No. 60/884,846, entitled“Three-Dimensional Lithium Battery Separator Architectures,” filed onJan. 12, 2007; all of which are hereby incorporated by reference hereinin their entirety.

BACKGROUND OF THE INVENTION

1. Technical Field of the Invention

Implementations consistent with the principles of the inventiongenerally relate to the field of battery technology, more specificallyto three-dimensional energy storage systems and devices, such asbatteries and capacitors, and methods of manufacturing thereof.

2. Background

Existing energy storage devices, such as batteries, fuel cells, andelectrochemical capacitors, typically have two-dimensional laminararchitectures (e.g., planar or spiral-wound laminates) with a surfacearea of each laminate being roughly equal to its geometrical footprint(ignoring porosity and surface roughness).

FIG. 1 shows a cross sectional view of an existing energy storagedevice, such as a lithium-ion battery. The battery 15 includes a cathodecurrent collector 10, on top of which a cathode 11 is assembled. Thislayer is covered by a separator 12, over which an assembly of an anodecurrent collector 13 and an anode 14 are placed. This stack is sometimescovered with another separator layer (not shown) above the anode currentcollector 13, and is rolled and stuffed into a can to assemble thebattery 15. During a charging process, lithium leaves the cathode 11 andtravels through the separator 12 as a lithium ion into the anode 14.Depending on the anode 14 used, the lithium ion either intercalates(e.g., sits in a matrix of an anode material without forming an alloy)or forms an alloy. During a discharge process, the lithium leaves theanode 14, travels through the separator 12 and passes through to thecathode 11.

Three-dimensional batteries have been proposed in the literature as waysto improve battery capacity and active material utilization. It has beenproposed that a three-dimensional architecture may be used to providehigher surface area and higher energy as compared to a two dimensional,laminar battery architecture. There is a benefit to making athree-dimensional energy storage device due to the increased amount ofenergy that may be obtained out of a small geometric area.

The following references may further help to illustrate the state of theart, and are therefore incorporated by reference as non-essentialsubject matter herein: Long et. al., “Three-Dimensional BatteryArchitectures,” Chemical Reviews, (2004), 104, 4463-4492; Chang Liu,FOUNDATIONS OF MEMS, Chapter 10, pages 1-55 (2006); Kanamura et. al.,“Electrophoretic Fabrication of LiCoO₂ Positive Electrodes forRechargeable Lithium Batteries,” Journal of Power Sources, 97-98 (2001)294-297; Caballero et al., “LiNi_(0.5)Mn_(1.5)O₄ thick-film electrodesprepared by electrophoretic deposition for use in high voltagelithium-ion batteries,” Journal of Power Sources, 156 (2006) 583-590;Wang and Cao, “Li⁺-intercalation Electrochemical/ElectrochromicProperties Of Vanadium Pentoxide Films By Sol ElectrophoreticDeposition,” Electrochimica Acta, 51, (2006), 4865-4872; Nishizawa etal., “Template Synthesis of Polypyrrole-Coated Spinel LiMn₂O₄Nanotubules and Their Properties as Cathode Active Materials for LithiumBatteries,” Journal of the Electrochemical Society, 1923-1927, (1997);Shembel et. al., “Thin Layer Electrolytic Molybdenum Oxysulfides ForLithium Secondary Batteries With Liquid And Polymer Electrolytes,”5^(th) Advanced Batteries and Accumulators, ABA-2004, Lithium PolymerElectrolytes; and Kobrin et. al., “Molecular Vapor Deposition—AnImproved Vapor-Phase Deposition Technique of Molecular Coatings for MEMSDevices,” SEMI Technical Symposium: Innovations in SemiconductorManufacturing (STS: ISM), SEMICON West 2004, 2004 SemiconductorEquipment and Materials International.

It would be desirable to make three-dimensional electrochemical energydevices that may provide significantly higher energy and power density,while addressing the above issues or other limitations in the art.

SUMMARY OF THE INVENTION

Various methods and apparatus relating to three-dimensional batterystructures and methods of manufacturing them are disclosed and claimed.In certain embodiments, a three-dimensional battery comprises a batteryenclosure, and a first structural layer within the battery enclosure,where the first structural layer has a first surface, and a firstplurality of conductive protrusions extend from the first surface. Afirst plurality of electrodes is located within the battery enclosure,where the first plurality of electrodes includes a plurality of cathodesand a plurality of anodes, and wherein the first plurality of electrodesincludes a second plurality of electrodes selected from the firstplurality of electrodes, each of the second plurality of electrodesbeing in contact with the outer surface of one of said first pluralityof conductive protrusions.

Other aspects and advantages of the present invention may be seen uponreview of the figures, the detailed description, and the claims thatfollow.

BRIEF DESCRIPTION OF THE DRAWINGS

Some embodiments of the invention are described with reference to thefollowing figures.

FIG. 1 is a generic cross-section of an existing two-dimensional energystorage device such as a lithium ion battery.

FIG. 2 is a schematic illustration of a backbone structure according toan embodiment of the invention.

FIGS. 3A-3D are schematic illustrations of some shapes into whichbackbone structures may be assembled according to certain embodiments ofthe invention.

FIGS. 4A-4E depict a schematic representation of a process formanufacturing a backbone structure using a subtractive reactive ion etchprocess, according to an embodiment of the invention.

FIGS. 5A-5D depict a schematic representation of a process formanufacturing a backbone structure using a subtractive electrochemicaletch process, according to an embodiment of the invention.

FIGS. 6A-6C depict a schematic representation of a process formanufacturing a backbone structure using a subtractive stamping process,according to an embodiment of the invention.

FIGS. 7A-7D depict a schematic representation of a process formanufacturing a backbone structure using an additive electrochemicaldeposition, electroless deposition, or electrophoretic depositionprocess, according to an embodiment of the invention.

FIGS. 8A-8E depict a schematic representation of a process formanufacturing a backbone structure using an additive extrusion process,according to an embodiment of the invention.

FIGS. 9A-9C depict a schematic representation of a process formanufacturing a backbone structure using a sequential deposition andassembly process, according to an embodiment of the invention.

DETAILED DESCRIPTION

Certain embodiments of the invention relate to the design of athree-dimensional lithium-ion battery. Existing energy storage devices,such as batteries, fuel cells, and electrochemical capacitors, typicallyhave two-dimensional laminar architectures (e.g., planar or spiral-woundlaminates) with a surface area of each laminate being roughly equal toits geometrical footprint (ignoring porosity and surface roughness). Athree-dimensional energy storage device can be one in which an anode, acathode, and/or a separator are non-laminar in nature. For example, ifelectrodes protrude sufficiently from a backplane to form a non-laminaractive battery component, then the surface area for such a non-laminarcomponent may be greater than twice the geometrical footprint of itsbackplane. In some instances, given mutually orthogonal X,Y,Zdirections, a separation between two constant-Z backplanes should be atleast greater than a spacing between electrodes in an X-Y plane, dividedby the square root of two.

Some embodiments of the invention relate to the use of a backbonestructure for the manufacture of three-dimensional energy storagedevices, such as batteries, capacitors, and fuel cells. The backbonestructure may be used for the purpose of providing mechanical stability,electrical connectivity, and increased surface area per unit geometricalarea. By way of example, the backbone structure may be made in the shapeof pillars by wire-bonding aluminum on a flat substrate, which may besubsequently coated with a cathode or anode material for the purpose ofassembling a battery. Examples of backbone formation using variousmaterials, shapes, and methodologies are presented herein, among otherembodiments.

Three-dimensional energy storage devices may produce higher energystorage and retrieval per unit geometrical area than conventionaldevices. Three-dimensional energy storage devices may also provide ahigher rate of energy retrieval than two-dimensional energy storagedevices for a specific amount of energy stored, such as by minimizing orreducing transport distances for electron and ion transfer between ananode and a cathode. These devices may be more suitable forminiaturization and for applications where a geometrical area availablefor a device is limited and/or where energy density requirement ishigher than what may be achieved with a laminar device.

Some embodiments of the invention include a mechanically stable,electrically conductive backbone structure that ends up being a part ofthe final assembled energy storage device. A backbone material typicallydoes not take an active part in electrochemical reactions of the energystorage device, and may enhance mechanical and electrical robustness.

The backbone material may also act as a high surface area substrate formanufacturing the high surface area electrochemical device. Mechanicalrobustness may increase the lifetime of the device, since activematerials that constitute the device are typically porous electrodeswith relatively lower mechanical stability. Electrical conductivity mayenhance or maintain a power density of the device (e.g., by decreasingresistivity) while also equalizing current distribution betweenelectroactive species.

A backbone structure may be made in any shape that provides highersurface area relative to geometrical area, such as pillars, posts,plates, waves, circles, diamonds, spirals, staircase structures, and soforth. The backbone structure may be made out of any material that maybe shaped, such as metals, semiconductors, organics, ceramics, andglasses. The backbone structure may serve to provide: (i) rigidity toactive electrodes in an energy storage device, such as anodes andcathodes in a lithium ion battery; (ii) electrical connectivity to tallthree-dimensional structures; and (iii) increased surface area per unitgeometrical area. Desirable materials include semiconductor materialssuch as silicon and germanium. Carbon-based organic materials may alsobe used to form backbone structures for three-dimensional shaping.Metals, such as aluminum, copper, nickel, cobalt, titanium, andtungsten, may also be used for backbone structures.

In some embodiments, a backbone structure is made out of a metal,semiconductor, organic material, ceramic, or glass using a subtractiveformation technique. These materials may be processed by reactivelyetching a substrate using a selective etch mask and a plasma etchprocess. Alternatively, or in conjunction, electrochemical etching,stamping, or electrical discharge machining may be used to selectivelyremove material preferentially in areas where these materials are notdesired.

In other embodiments, a backbone structure is made out of a metal,semiconductor, organic, ceramic, or glass using an additive formationtechnique. These materials may be processed by making a sacrificial moldusing a technique such as conventional lithography, and depositing abackbone material using techniques such as electrochemical deposition,electroless deposition, electrophoretic deposition, vacuum assistedfilling, stencil assisted filling, and so forth. In certain cases, thebackbone structure may be assembled directly using a wirebondingprocess. In other cases, the backbone structure may be made on a flatplate using conventional lithography and deposition techniques, andsubsequently assembled by “pick and place” and soldering or gluingtechniques.

In other embodiments, a backbone material may be shaped using printingtechniques, such as three-dimensional printing and inkjet printing, toform a backbone structure using single or multiple layers of printing toobtain a desired shape and thickness. Alternatively, or in conjunction,the backbone material may be assembled in the form of layered sheets,with sacrificial layers deposited in between. After stacking of thesheets is substantially complete, a resulting structure is cut intopieces of a desired height, assembled together, and the sacrificialmaterial is released to provide the backbone structure.

In the case of an electrically conductive backbone structure, an activematerial may be directly assembled on top of and around the backbonestructure by various techniques, such as electrochemical deposition,electroless deposition, co-deposition in an organic or inorganic matrix,electrophoretic deposition, mechanical filling and compacting, andvacuum assisted flow deposition.

In case of an electrically non-conductive backbone structure, aconducting layer may be deposited by various techniques, such aselectrochemical or electroless deposition, vapor assisted vacuumdeposition such as Atomic Layer Deposition (ALD) and Chemical VaporDeposition (CVD), sputter deposition, evaporation, and electrophoreticdeposition. This conductive layer may be subsequently removed in orderto remove an electrical connection between an anode and a cathode. Thisremoval may be accomplished using techniques such as sputter etching,ion milling, and liftoff. In addition, techniques such as chemicaldissolution may be used with standard techniques such as lithography toprotect areas that do not need to be removed.

FIG. 2 illustrates an exemplary concept of a backbone structure 20 usedin the formation of a three-dimensional battery. FIG. 2 shows across-sectional schematic of two positive electrodes 21 and a negativeelectrode 23. In this embodiment, the backbone structure 20 includes anon-conductive base 24 of a common material on which a conductivematerial 22 has been deposited and removed in the areas where it is notneeded in order to separate the electrodes 21 and 23. It is apparentfrom comparing FIG. 2 and FIG. 1 that a surface area for the electrodes21 and 23 in FIG. 2 is relatively higher as compared to the surface areafor the electrodes shown in FIG. 1, calculating this area as a productof a length L and a thickness T of the electrodes 21 and 23. It shouldbe noted that the thickness, and therefore related properties such asconductivity, of various features (such as electrodes and backbonestructure protrusions) according to certain embodiments may be variedlocally (e.g., from electrode to electrode or from protrusion toprotrusion) based on current-carrying requirements or other relevantperformance specifications.

Some examples of three-dimensional architectures that are capable of usewith certain embodiments of the present invention, and that havecathodes and anodes protruding from the same backplane, are shown inFIGS. 3A-3D. FIG. 3A shows a three-dimensional assembly with cathodesand anodes in the shape of pillars, FIG. 3B shows a three-dimensionalassembly with cathodes and anodes in the shape of plates, FIG. 3C showsa three-dimensional assembly with cathodes and anodes in the shape ofconcentric circles, and FIG. 3D shows a three-dimensional assembly withcathodes and anodes in the shape of waves. Other configurations, such ashoneycomb structures and spirals might also be used with certainembodiments of the present invention. In FIGS. 3A-3D, cathodes 30 andanodes 31 protrude from the same backplane and are alternating in aperiodic fashion. However, in other embodiments the cathodes 30 mayprotrude from a different backplane than anodes 31.

FIGS. 4A-4E depict a schematic representation of an overall process flowfor manufacturing a backbone structure using a subtractive reactive ionetch process according to certain embodiments. The process involvesusing a substrate 40 that may be shaped using a directional plasmasource to form a volatile gaseous by-product, thereby facilitating itsremoval. A non-limiting example of the substrate 40 is one formed ofsilicon, which may be single-crystal or polycrystalline in nature. Amasking layer 41 is deposited on top of the substrate 40 by methods suchas vacuum deposition, thermal oxidation, surface coating, and wetchemical deposition. In the case of silicon as the substrate 40, athermally grown silicon dioxide layer of a particular thickness mayserve as the masking layer 41. This layer 41 may be subsequentlypatterned by standard patterning techniques such as lithography in orderto provide a pattern suitable for further processing to create thebackbone structure. In some embodiments of the invention, the maskinglayer 41 may be covered with a second masking layer 42 that is used topattern the first masking layer 41 (see FIGS. 4A-4B). In this case, thefirst masking layer 41 is patterned by using the second masking layer 42as a stencil (see FIG. 4C). For the silicon/silicon dioxide case, astandard photoresist may be used as the second masking layer 42. Thesecond masking layer 42 may be patterned with standard opticallithography techniques. The second masking layer 42 may be selectivelyremoved using selective wet or dry methods, leaving behind the patternedfirst masking layer 41 (see FIG. 4D). This combination of the substrate40 and the patterned first masking layer 41 is subjected to adirectional plasma 43 in a controlled environment in order to transferthe image of the first masking layer 41 onto the substrate 40 (see FIG.4D). This reactive etch process in the presence of a directional plasmasource may provide excellent anisotropic etching of the substrate 40while etching the masking layer 41 itself at a very low rate. After thereactive etch of the substrate 40 is substantially complete, the maskinglayer 41 may be removed to leave the patterned substrate 40 behind,thereby forming the backbone structure (see FIG. 4E).

The following example further explains concepts described with referenceto FIGS. 4A-4E. Single-crystal or polycrystalline silicon may be used asthe substrate 40 that may be etched directionally in the presence of aplasma. The first masking layer 41 may be a thermally grown silicondioxide layer of a particular thickness. A standard photoresist, such asAZ4620™ and AZP4620™ (commercially available from Clariant Corporation),may be used as the second masking layer 42. This layer 42 may be spincoated on top of the silicon dioxide layer, and subsequently patternedwith standard optical lithography techniques. The areas of thephotoresist that are exposed to light may be developed away using adeveloper solution, such as AZ400K™ (commercially available fromClariant Corporation). This patterned structure is dipped in a solutionof HF, NH₃F, and water (Buffered Oxide Etch), wherein exposed silicondioxide surfaces are dissolved. The remaining photoresist may beselectively removed by using a compatible organic solvent, such asN-methyl-2-Pyrrolidone, leaving behind the patterned silicon dioxidelayer. This combination of the silicon and patterned silicon dioxide maybe subjected to a directional fluoride plasma source in order to etch animage of the silicon dioxide layer onto the substrate 40. Thedirectionality of the plasma 43 is controlled by a bias voltage betweenan anode and a cathode in a conventional plasma reactive ion etcher. Adifference in rate between etch of silicon and silicon dioxide causes apattern to be transferred to the substrate 40 without much etching in alateral direction. After the reactive etch of silicon is substantiallycomplete, the masking layer 41 may be removed by immersion in theBuffered Oxide Etch solution to leave the patterned substrate 40 behind.In some cases, a stop layer can be added to the bottom of the substrate40 to facilitate complete etching and isolation of the cathode and anodebackbone structures.

In some embodiments, the patterned substrate 40 is electricallyconductive, in which case the resulting backbone structure is ready forfurther processing of active materials. In certain other embodiments,the backbone structure is electrically non-conductive. In this case,further processing by deposition of a conductive layer may be performedby various methods.

FIGS. 5A-5D depict a schematic representation of a process formanufacturing a backbone structure using a subtractive electrochemicaletch process according to certain embodiments. In these particularembodiments, a substrate 50 is patterned using a electrically insulatingmasking layer 51 that is deposited on top of the substrate 50 by methodssuch as vacuum deposition, thermal oxidation, surface coating, and wetchemical deposition. This layer 51 is subsequently patterned by standardpatterning techniques such as lithography in order to provide a patternsuitable for further processing to create the backbone structure. Insome embodiments of the invention, the masking layer 51 is covered witha second masking layer 52 that is used to pattern the first maskinglayer 51 (see FIGS. 5A-5B). In this case, the first masking layer 51 ispatterned by using the second masking layer 52 as a stencil. The secondmasking layer 52 is selectively removed using selective wet or drymethods, leaving behind the patterned first masking layer 51 (see FIG.5B). The combination of the substrate 50 and the first masking layer 51is placed in an electrochemical cell 53 that has a counter electrode 54and a nozzle 55 that delivers a solution used to electrochemicallyremove a material in areas that are exposed to the solution (see FIG.5C). In certain embodiments, the whole workpiece may be dipped into thesolution that may dissolve the material that is in contact with thesolution. However, the illustrated process may be more isotropic innature, and typically an amount of material removed in the depthdirection D may be substantially the same as the amount of materialremoved in each side of the width direction W. A dip-tank solution maybe used for making features in which gaps G in the resulting backbonestructure are significantly narrower than the width W. A DC power source56 may be used to apply a potential that is sufficient to remove thematerial in contact with the solution. The process is substantiallycomplete when essentially the desired amount of material is removed,which may be controlled based on the rate of etching that has beenpreviously determined. In certain other cases, a current may bemonitored, and a drop in the current may correspond to an end-point ofthe electrochemical reaction. After the reaction is substantiallycomplete, the workpiece is removed, and the masking layer 51 may beremoved to leave the patterned substrate 50 behind, thereby forming thebackbone structure.

The following example further explains concepts described with referenceto FIGS. 5A-5D. One example of the substrate 50 for electrochemicalpatterning is a copper sheet. A sheet of the desired thickness may beused as the substrate 50, and may be patterned using the electricallyinsulating masking layer 51 (e.g., AZ4620™ or AZP4620™ photoresist) thatis deposited on top of the substrate 50 by spin coating. This layer 51may be exposed to light in the presence of a photomask that blocks lightto areas in which the resist should be left behind. The workpiece may beplaced in a solution that selectively removes the exposed areas. Thecombination of the substrate 50 and the first masking layer 51 is placedin the electrochemical cell 53 that has the counter electrode 54 (e.g.,platinum) and the nozzle 55 that delivers the electrochemical etchsolution used to electrochemically remove the metal in areas that areexposed to the solution. A combination of 10 wt % sulfuric acid and 1 wt% hydrogen peroxide may be delivered through the nozzle 55 to theworkpiece. The DC power source 56 may be used to apply an anodicpotential to the substrate 50, which removes copper in areas where thesolution comes in contact with the copper anode and the platinum cathodeat the same time, thereby forming a local electrochemical cell. Afterthe reaction is substantially complete, the workpiece may be removed,and the masking layer 51 may be removed with N-methyl-2-pyrrolidone toleave the patterned substrate 50 behind.

FIGS. 6A-6C depict a schematic representation of a process formanufacturing a backbone structure using a subtractive stamping processaccording to certain embodiments. A mandrel 60 is pre-fabricated withpatterns that are inverted from a desired backbone pattern, and themandrel 60 is coated with a thin release layer 61 that may be used tofacilitate removal of the mandrel 60 after processing. The release layer61 may be, for example, an organic material that may be vapor-depositeduniformly into three-dimensional features. This material may haveadditional properties of having either poor adhesion or the ability tobe selectively etched without etching the mandrel 60 or a backbonematerial. For example, a stainless steel mandrel coated with a thinlayer of copper deposited by chemical vapor deposition may act as anadequate stamping device for a process where a material that is used asa mold is thermally curable photoresist (see FIG. 6A). The combinationof the mandrel 60 and the release layer 61 is contacted with a sheet ofmoldable material 62 that is on top of a substrate 63. Pressure isapplied in order to transfer the pattern to the moldable material 62(see FIG. 6B). This combination is hardened by curing into place themoldable material 62 using temperature or other means, such as light, incase the substrate 63 is transparent. The release layer 61 is removed bysuitable means while separating the mandrel 60 and the resultingbackbone structure that includes the molded material and the substrate64 (see FIG. 6C).

In certain other embodiments of the invention, additive processes may beused to process a backbone structure of an energy storage device. FIGS.7A-7D depict a schematic representation of a process for manufacturingthe backbone structure using an additive electrochemical depositionprocess according to certain embodiments. This process may be referredto as a LIGA process in the art, which in German stands for“lithography, galvano-forming and molding (Abformung).” In this process,a conductive or non-conductive substrate 70 is used. In case of anon-conducting substrate, a conducting layer 71 is deposited.Photoresist 72 is coated on top of this substrate 70, and is patternedby standard lithography techniques using a photomask 73 to leave behindthe photoresist 72 in areas where a backbone material is not to bedeposited (see FIGS. 7A and 7B). The workpiece is placed in anelectroplating bath with a potential enough to reduce metallic ionspresent in solution to form a metal 74 (see FIG. 7C). The metallic ionsare reduced at a conductive surface and are not deposited where thephotoresist 72 is present. When the process is substantially complete,the workpiece including components 70, 72, and 74 is removed from aplating cell, and the photoresist 72 is removed to leave the backbonestructure (including components 70 and 74) behind (see FIG. 7D).

The following example further explains concepts described with referenceto FIGS. 7A-7D. In this process, a silicon wafer may be used as thesemi-conductive substrate 70. Copper may be deposited using sputterdeposition to create the conductive layer 71 on top of the silicon. Apositive or negative tone photoresist 72 (e.g., AZ4620™ or AZP4620™) maybe coated on top of this substrate 70 and patterned by standardlithography techniques to leave behind the photoresist 72 in areas wherea backbone material is not to be deposited. This workpiece may be placedin a nickel electroplating bath including 1 M nickel sulfate, 0.2 Mnickel chloride, 25 g/l boric acid, and 1 g/l sodium saccharin, alongwith a platinum counter electrode and a potential enough to reducenickel ions present in the solution to Ni metal 74. The metal ions arereduced at a conductive surface and are not deposited where thephotoresist 72 is present. When the process is substantially complete,the workpiece including the silicon wafer 70, photoresist 72, and nickelmetal 74 may be removed. Subsequently, the photoresist 72 may be removedusing N-methyl-2-pyrrolidone to leave the backbone structure includingcomponents 70 and 74 behind. The remaining copper metal in the areawhere the photoresist 72 was present may be removed by a chemical etchinvolving 2% sulfuric acid and 1% hydrogen peroxide.

FIGS. 8A-8E depict a schematic representation of a process formanufacturing a backbone structure using an additive extrusion processaccording to certain embodiments. A mandrel 80 is pre-fabricated withpatterns that are inverted from a desired backbone pattern, and themandrel 80 is coated with a thin release layer 81 that may be used tofacilitate removal of the mandrel 80 after processing (see FIG. 8A).This mandrel 80 also has openings either at the edges or on top of eachopening 85 in order to facilitate the addition of a material that may bemade into a mold. The release layer 81 may be, for example, an organicmaterial that may be vapor-deposited uniformly into three-dimensionalfeatures. This material may have additional properties of having eitherpoor adhesion or the ability to be selectively etched without etchingthe mandrel 80 or a backbone material. For example, a stainless steelmandrel coated with a thin layer of copper deposited by chemical vapordeposition may act as an adequate stamping device for a process where amaterial that is used as the moldable material 82 is a thermally curablephotoresist. The combination of the mandrel 80 and the release layer 81is contacted with a substrate 83 (see FIG. 8B). The moldable material 82is extruded into the openings 85 and filled (see FIG. 8C). Any residualmaterial within the openings 85 is cleaned out at this time (see FIG.8D). This combination is hardened by curing into place the moldablematerial 82 using temperature or other means, such as light, in case thesubstrate 83 is transparent. The release layer 81 is removed by suitablemeans while separating the mandrel 80 and the resulting backbonestructure that includes the molded material 82 and the substrate 83 (seeFIG. 8E). Depending on the requirements of each particularimplementation, release layer 81 may not be necessary (e.g., if themandrel/mold 80 itself satisfies the required characteristics that wouldotherwise be satisfied by a release layer). In certain embodiments, themandrel/mold 80 may be released by dissolution.

FIGS. 9A-9C depict a schematic representation of an exemplary processfor manufacturing a backbone structure using a sequential deposition andassembly process according to certain embodiments. In this process,alternating layers of backbone material and a sacrificial material areassembled. An example of a set of materials that may be assembledtogether are sheets of polyethylene terephthalate (PET) 90 interspersedwith copper foils 91. The resulting stack thus includesPET/copper/PET/copper/PET (see FIG. 9A). The layers are diced to athickness substantially corresponding to a height of a backbonestructure H, spirally wound within their axes, and assembled onto asubstrate 92 using epoxy glue (see FIG. 9B). A sacrificial PET layer isremoved by selectively etching it away in a selective chemical etchsolution containing sodium hypochlorite (NaOCl). This leaves behind twospirally wound copper substrates, one for cathode backbone and anotherfor anode backbone with gaps in the middle which will house activematerials and separators for an electrochemical energy device (see FIG.9C).

Once a backbone structure is available, materials that are involved inelectrochemical reactions, also called active materials, may be loadedonto the backbone structure. This may be done by several differentmethods. An anode backbone and a cathode backbone may be separate fromeach other, but each electrode may be electrically conductive by itself.This lends to electrochemical deposition techniques and electrophoreticdeposition techniques as viable options for adding the active materials.For example, in the case of a lithium-ion battery, a cathode material,such as LiCoO₂, LiNi_(0.5)Mn_(1.5)O₄, Li(Ni_(x)Co_(y)Al_(z))O₂, LiFePO₄,or Li₂MnO₄ may be electrophoretically deposited onto a conductivesubstrate. Electrophoretic deposition may also be performed for V₂O₅films. Cathode materials may also be co-deposited along with apolypyrrole matrix. In addition, certain cathode materials forlithium-ion batteries may be electrochemically deposited, such asmolybdenum oxysulfides. In certain embodiments, cathode formationcomprises electrophoretic deposition of LiCoO₂ until a layer thicknessbetween 1 micron and 300 microns is formed. In certain embodiments, thelayer thickness is between 5 microns and 200 microns, and in certainembodiments, the layer thickness is between 10 microns and 150 microns.With regards to anode materials, electrochemical deposition may be usedfor plateable anode materials, such as tin, electrophoretic depositionmay be used to assemble graphite, and an electrophoretic resistdeposition followed by pyrolysis may form a carbon anode. Other suitableanode materials may include titanates, silicon, and aluminum. Similarlayer thicknesses apply to anode formation as described above. Suitableseparator materials may include polyethylenes, polypropylenes, TiO₂,SiO₂, Al₂O₃, and the like.

While some embodiments have been described with reference to energystorage devices, it should be recognized that the backbone structuresdescribed herein may be useful in various other types of devices toprovide increased surface area per unit geometrical area (or per unitweight or volume). These other types of devices may involve varioustypes of processes during their operation, such as heat transfer,chemical reactions, and diffusion.

While the invention has been described with reference to the specificembodiments thereof, it should be understood by those skilled in the artthat various changes may be made and equivalents may be substitutedwithout departing from the true spirit and scope of the invention asdefined by the appended claims. In addition, many modifications may bemade to adapt a particular situation, material, composition of matter,method, operation or operations, to the objective, spirit, and scope ofthe invention. All such modifications are intended to be within thescope of the claims appended hereto. In particular, while the methodsdisclosed herein have been described with reference to particularoperations performed in a particular order, it will be understood thatthese operations may be combined, sub-divided, or re-ordered to form anequivalent method without departing from the teachings of the invention.Accordingly, unless specifically indicated herein, the order andgrouping of the operations is not a limitation of the invention.

1-32. (canceled)
 32. A process for preparing a three-dimensional non-aqueous battery, comprising: forming a plurality of anode backbone structures and a plurality cathode backbone structures on a surface of a first structural layer, wherein each of the anode backbone structures and the cathode backbone structures comprises silicon, is connected to the surface of the first structural layer, and protrudes at least 50 microns from the surface of the first structural layer, forming a plurality of anodes on the anode backbone structures, forming a plurality of cathodes on the cathode backbone structures, the cathodes being separated from the anodes by gaps, and depositing a porous separator material in the gaps between the anodes and the cathodes.
 33. The process of claim 32 wherein the porous separator material is deposited by electrophoretic deposition.
 34. The process of claim 32 wherein the plurality of cathodes are formed by electrophoretically depositing a cathode material on the plurality of cathodes.
 35. The process of claim 32 wherein the anode and cathode backbone structures comprise fins protruding at least 50 microns from the surface of the first structural layer.
 36. The process of claim 32 wherein the anode and cathode backbone structures comprise fins protruding at least 50 microns from the surface of the first structural layer and having a thickness less than 20 microns.
 37. The process of claim 32 wherein the anode and cathode backbone structures comprise pillars protruding at least 50 microns from the surface of the first structural layer.
 38. The process of claim 32 wherein the anode and cathode backbone structures comprise cylindrical pillars protruding at least 50 microns from the surface of the first structural layer.
 39. The process of claim 32, wherein forming the anodes comprises depositing a layer of an anodically active material onto the outer surface of the anode backbone structures.
 40. The process of claim 32, wherein forming the cathodes comprises depositing a layer of a cathodically active material onto the outer surface of the cathode backbone structures.
 41. The process of claim 32 wherein the anode and cathode backbone structures have an aspect ratio of approximately 2.5:1 to 500:1.
 42. The process of claim 32 wherein each of the anodes is associated a current collector to form a non-planar active battery component.
 43. The process of claim 32 wherein each of the cathodes is associated a current collector to form a non-planar active battery component.
 44. The process of claim 32 wherein each of the anodes has a thickness of 5 to 200 μM.
 45. The process of claim 32 wherein each of the anodes has a thickness of 10 to 150 μM.
 46. The process of claim 32 wherein each of the cathodes has a thickness of 5 to 200 μM.
 47. The process of claim 32 wherein each of the cathodes has a thickness of 10 to 150 μM.
 48. The process of claim 32 wherein each of the anodes and the cathodes has a thickness of 10 to 150 μM and the first cathode has a thickness of 10 to 150 μM. 